Steam-turbine.



PATENTED JUNE 16, 1903.

J. STUMPF. STEAM TURBINE.

APPLwATIoN FILED rms. 24. 190s'.

N0 MODEL.

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UNITED STATES l Patented J' une 16, 1903.

PATENT GEEICE.

STEAM -TU RBIN E,

SPECIFICATION forming part of Letters Patent No. 730,982, dated J' une 16, 1903. Application tiled February 24, 1903. Serial No. 144,679. (No model.)

It has been tried already to utilize the steamy or gas several times in the same turbinewheel, and return-buckets have been constru ctedfor this purpose which lead the steam leaving the buckets of the turbine-wheel once or several times again back into these buckets of the turbine wheel. By the steam streaming with a very considerable velocity in all modern turbines the pressure of the steam which has expanded when leaving the nozzles nearly up to the pressure of the condenser greatly increases again in the buckets in consequence of the centrifugal power arising by the streaming direction of the steam being reversed. I have found out that according to the circumstances the pressure of the steam which had perfectly expanded before entering the buckets was increased by the centrifugal power in the turbine-wheel buckets up to several atmospheres. This tension or pressure of the steam effects, during the passage of the steam from one bucket into the other one, a considerable scattering of the steam, and it even sometimes arrives, if the augmentation of the pressure in the buckets is not sufciently taken in consideration in constructing the buckets, that explosion-like expansions of the steam take place if the steam leaves the shovels, and in consequence hereof a great part of the steam will escape betweenthe shovel-rims and can consequently be no more used again. When considering that this process of increasing the pressure in the buckets and afterward expanding again takes place twice-that is to say, in the turbine-wheel buckets and in the by means of which, especiallyin case of great turbine-wh eels, an axial pressure arises which has a detrimental eect upon the bearings of the turbine-wheel. In order to do away with these disadvantages, I provide my new construction, in whichthe well-known doublebucket wheel is used. In these double-bucket.

wheels buckets of a double-U form are used, so that the steam is divided into two parts. These divided parts stream through a U- formed part of the buckets and are then taken up by the return-buckets, which for the purpose of avoiding a scattering of the steam have also a double- U or a similar form, so that the two divided steam-.jets unite again in the middle of the double return-buckets, so as to form one jet, which streams again into the buckets of the turbine-wheel and is here again divided into two jets. It is hereby perfectly indifferent that centrifugal pressures arise in the return-buckets, as the two divided steam-jets guide one another, and any loss in the middle of the turbine-wheel is avoided. Furthermore, an axial pressure in the turbine-wheel cannot occur, as the pressures areV the same on both sides. v

I n order to make myinvention more clear, I refer to the accompanying drawings, in which- Figure l is a longitudinal section through Vva part of one row of turbine-wheel buckets and return-buckets. Fig. 2 is part of a plan of the turbinewheel, showing the returnbuckets in dotted lines. Fig. 3 shows a special construction of the return-buckets.

The buckets a of the turbine-wheel have a double-U form. The return-buckets b have in the example shown halves or horns of different length, and the angle of inclinations of the horns is also different. The steam leaving the buckets d enters-into theshort horns b and is led by the long horns b? back into the buckets a. As may bevseen from Fig. 3, partitions c may be arranged Within the return-buckets, which partitions serve the purpose of insuring an equal division of the IOC steam-jet over the whole breadth of the return-buckets, so that that part of the turbine-wheel upon which the steam of the return-buckets is conducted is met by a uniform jet of steam, and chockng of the steam at the end of the return-bucket is therefore entirely avoided. lFurther it is advantagreens to close the horn d2 or even the whole bucket at theinsideby means of awall hereby forming rectangular channels which insure a proper guide for the steam. By thus inclosing the return-bucket the steam will be prevented from overflowing.

It will be understood that the invention is not restricted to the special form of buckets and return-bu ck ets shown, b ut is applicable to any form of double turbine Wheel buckets Aand of double return-buckets.

The invention may also be applied to turbines with double buckets and two rows of admission-nozzles, situated at the outside of the buckets, so that the admissionsteam streams through the turbine-wheel bucket, unites in the middleof the turbine-wheel bucket, is then divided up again in two parts by the return-buckets, and is led by these return-buckets back into the turbine-wheel buckets. Y

Having thus fully described the nature of this invention, what I desire to secure by Letters Patent of the United States is- 1. In a steam-turbine, the combination with admission-nozzles and a turbine-Wheel provided with double buckets, of double returnbuckets for returning the exhaust-steam on both sides into the turbine-wheel buckets, substantially as described and for the purpose set forth.

2. In a steam-turbine, the combination of admission-nozzles and a turbine-wheel provided with double buckets, with double return-buckets, and guide-ribs provided inside said return buckets, substantially as described and for the purpose set forth.

3. In a steam-turbine, the combination of admission-nozzles and a turbine-Wheel pro# vided with double buckets, with double return-buckets and closed guide-channels provided inside said return-buckets, substantially as described and for the purpose set forth.

In testimony whereof I have signed my name to this Specification in the presence of two subscribing witnesses.

JOHANN STUMPF.

Witnesses:

HENRY HASPER,

WOLDEMAR HAUPT. 

